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SUMMARY:First-principles dynamics applied to energy materials - Keith Refs
 on\, Rutherford Appleton Laboratory
DTSTART:20140130T141500Z
DTEND:20140130T151500Z
UID:TALK49269@talks.cam.ac.uk
CONTACT:Gareth Conduit
DESCRIPTION:One of the major developments in computational science over th
 e past decade and a half has been the rise of dynamical studies in materia
 ls science based on density-functional theory.  This has enabled a new clo
 se-coupling of computational dynamics with experimental spectroscopy which
  can add value and impact to both.\n\nI will discuss how dynamical propert
 ies of materials may be approached from the low-temperature crystalline or
  high-temperature disordered state by lattice dynamics or molecular dynami
 cs methods respectively. Much simulation effort is devoted towards underst
 anding the properties of materials used in engineered systems for energy c
 onversion\, transport and storage.  First principles lattice dynamics calc
 ulations have revealed the existence of anharmonic “Rattler” modes in 
 the layered thermoelectric material NaxCoO2\, as a consequence of large pe
 riod ordered superstructures. These lower the thermal conductivity nearly 
 six-fold\, and so increase the thermoelectric "figure of merit" by the sam
 e factor.  I will also discuss dynamical disorder in the superionic conduc
 tor LiBH4\, and show how only a full molecular-dynamics treatment is capab
 le of describing the phase transition and superionic state. Even then\, a 
 further development of MD - ab initio non-equilibrium molecular dynamics -
  is required to model the Li ion transport in the high-temperature phase.\
 n
LOCATION:TCM Seminar Room\, Cavendish Laboratory
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